Engineering Ag-Co interfacial sites for selective catalytic reduction of nitric oxide by isopropyl alcohol from semiconductor FAB process

초록

Selective catalytic reduction (SCR) has long been explored for NOx abatement using diverse reductants across a variety of industrial emission sources. Isopropyl alcohol (IPA), a common constituent of semiconductor fabrication facility (FAB) exhaust, offers particular promise as a process-derived oxygenated reductant for the simultaneous removal of NOx and VOCs. However, the H2O-deficient nature of FAB exhaust fundamentally alters reductant activation on conventional Ag/Al2O3 catalysts: they preferentially dehydrate IPA to propene, a pathway that is unfavorable for effective NO reduction. Here, we show that co-impregnated AgCo/Al2O3 overcomes this limitation by forming structurally integrated Ag-O-Co interfacial sites on alumina. Microscopic and spectroscopic analyses reveal that Co incorporation competes for AlV anchoring sites, weakens the electrondeficient and acidic character of Ag, and reorganizes the local interfacial environment. This interfacial structure suppresses unproductive dehydration, promotes oxygenated activation of IPA, and allows dehydrationderived propene to be redirected into an acetone-mediated SCR sequence through enol/acetate and subsequent -NCO/-CN intermediates. As a result, Ag1Co5/Al2O3 maintains high deNOx activity under simulated FAB exhaust, achieving >80% NO conversion even at 1.6% H2O, where Ag1/Al2O3 is strongly deactivated. The same mechanistic advantage is retained in a scaled monolith reactor, which delivers 84% NO conversion with 80% CO2 selectivity at 350 degrees C and remains stable for 100 h. These findings identify interfacial control of reductant activation as a practical design principle for SCR catalysts operating under H2O-deficient conditions.

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